1. Field of the Invention
This invention relates to a plasma display panel, and more particularly to a plasma display panel that permits a high-speed addressing. Also, the present invention is directed to a method of driving said plasma display panel.
2. Description of the Related Art
Recently, a plasma display panel (PDP) feasible to a manufacturing of a large-dimension panel has been highlighted as a flat panel display device. The PDP typically includes a three-electrode, alternating current (AC) surface discharge PDP that has three electrodes and is driven with an AC voltage as shown in FIG. 1.
Referring to FIG. 1, a discharge cell of the three-electrode, AC surface discharge PDP includes a scanning/sustaining electrode 12Y and a common sustaining electrode 12Z formed on an upper substrate 10, and an address electrode 20X formed on a lower substrate 18. On the upper substrate 10 in which the scanning/sustaining electrode 12Y is formed in parallel to the common sustaining electrode 12Z, an upper dielectric layer 14 and a protective film 16 are disposed. Wall charges generated upon plasma discharge are accumulated in the upper dielectric layer 14. The protective film 16 prevents a damage of the upper dielectric layer 14 caused by the sputtering generated during the plasma discharge and improves the emission efficiency of secondary electrons. This protective film 16 is usually made from MgO. A lower dielectric layer 22 and barrier ribs 24 are formed on the lower substrate 18 provided with the address electrode 20X, and a fluorescent material 26 is coated on the surfaces of the lower dielectric layer 22 and the barrier ribs 24. The address electrode 20X is formed in a direction crossing the scanning/sustaining electrode 12Y and the common sustaining electrode 12Z. The barrier ribs 24 is formed in parallel to the address electrode 20X to prevent an ultraviolet ray and a visible light generated by the discharge from being leaked to the adjacent discharge cells. The fluorescent material 26 is excited by an ultraviolet ray generated upon plasma discharge to produce a red, green or blue color visible light ray. An active gas for a gas discharge is injected into a discharge space defined between the upper/lower substrate and the barrier rib.
As shown in FIG. 2, such a discharge cell is arranged in a matrix type. In FIG. 2, the discharge cell 1 is provided at each intersection among scanning/sustaining electrode lines Y1 to Ym, common sustaining electrode lines Z1 to Zm and address electrode lines X1 to Xn. The scanning/sustaining electrode lines Y1 to Ym are sequentially driven while the common sustaining electrode lines Z1 to Zm are commonly driven. The address electrode lines X1 to Xn are driven with being divided into odd-numbered lines and even-numbered lines.
Such a three-electrode, AC surface discharge PDP is driven with being separated into a number of sub-fields. In each sub-field interval, a light emission having a frequency proportional to a weighting value of a video data is conducted to provide a gray scale display. For instance, if a 8-bit video data is used to display a picture of 256 gray scales, then one frame display interval (e.g., 1/60 second=16.7 msec) in each discharge cell 1 is divided into 8 sub-fields SF1 to SF8 as shown in FIG. 3. Each sub-field is again divided into a reset interval, an address interval and a sustaining interval. A weighting value at a ratio of 1:2:4:8: . . . :128 is given to the sustaining interval.
FIG. 4 is waveform diagrams of driving signals applied to each electrode line of the PDP for each sub-field in the conventional driving method. Referring to FIG. 4, one sub-field is divided into a reset interval for initializing an entire field, an address interval for scanning the entire field on a line-sequence basis to write a data, and a sustaining interval for sustaining a luminescent state of the discharge cells 1 into which the data has been written. First, in the reset interval, a reset pulse is applied to the scanning/sustaining electrode lines Y to generate a reset discharge for initializing the discharge cells. At this time, a direct current for preventing an erroneous discharge is applied to the address electrode lines X. In the address interval, a scanning pulse SP is sequentially applied to the scanning/sustaining electrode lines Y and a data pulse Va synchronized with the scanning pulse SP is applied to the address electrode lines X. At this time, a desired level of direct current voltage is applied to the common sustaining electrode lines Z. This direct current voltage allows a stable address discharge to be generated between the address electrode line X and the scanning/sustaining electrode line Y. In the sustaining interval, a sustaining pulse SUS are alternately applied to the scanning/sustaining electrode lines Y and the common sustaining electrode lines Z to cause a sustaining discharge at the discharge cells selected in the address interval.
In the conventional PDP driven as mentioned above, in order to obtain a stable discharge characteristic during the address discharge, a pulse width Td of the data pulse Va for each sub-field is set to more than 2.5 μs. If a pulse width Td of the data pulse Va is set to a large value of more than 2.5 μs, then it is possible to prevent an erroneous discharge from being generated due to a discharge delay phenomenon that is an inherent property of the PDP. However, if so, a ratio occupied by the sustaining interval having an influence on real picture brightness in one frame of 16.67 ms is reduced to less than 30% to deteriorate picture brightness. Furthermore, in order to reduce a contour noise that is an inherent picture quality deterioration phenomenon of the PDP, the number of sub-fields in one frame interval is enlarged from eight into ten to twelve. However, if the number of sub-fields in the fixed one frame interval is enlarged, then each sub-field interval is shortened to that extent. In this case, since an address interval is fixed and a sustaining interval only is shortened for each sub-field so as to obtain a stable address discharge, picture brightness is lowered. Moreover, in the case of a high-resolution PDP having a very large number of scanning/sustaining electrode lines Y, a sustaining interval is too shortened to make a display itself. In the high-resolution PDP, the number of scanning lines has much larger value to more lengthen an address interval at which the scanning lines are sequentially driven for each sub-field. As a result, a sustaining interval is inevitably reduced during the fixed one frame interval to cause brightness deterioration.